The present invention relates generally to a fluid purification system and more particularly to a fluid purification system which does not use fittings and therefore is more reliable against leaks. The present invention also relates to a fluid purification system to which control and monitoring devices may be easily attached.
A number of water purification systems which are intended for commercial and household use are presently available. Available household systems include both under-the-counter as well as counter-top units. Such available systems typically include a number of water treatment filters or filter elements such as prefilters, ultraviolet water treatment devices, reverse osmosis membrane filters and postfilters through which feedwater is processed. Although such available systems provide an adequate filtration system, they are typically unsightly, and bulky, and difficult to install and remove. Such filter units typically include a number of fittings which are used to connect the filtration system to various external water processing or holding components through a number of tubes. Further, in most available systems, replacement of the individual filters require a fair amount of labor to remove and install a new filter.
In presently available systems, external devices such as control or monitoring devices are generally not integrated into the system and therefore are more difficult to attach. Further, available fluid treatment systems were not designed to incorporate additional devices and therefore do not possess the aesthetic qualities of the present invention.
For example, one known water filter systems is disclosed in U.S. Pat. No. 1,942,584 (Weinstein). The filter disclosed in this reference includes a one-piece casing having a plurality of partitions which divide the casing into a plurality of compartments. Each of the compartments is used as a housing for various filtering means. The system includes a number of tubes connected to the casing for transferring fluid from one compartment to another compartment. Separate external tubes are provided for functions such as bypassing a particular filter. The system also includes a plug at the bottom of each compartment which may be used to conduct water in a direction reverse to its normal flow in order to force accumulation or buildup of materials from the face of the filters. A threaded opening is provided at one end for admitting the fluid into the first filter compartment and a second threaded opening is provided at the opposite end of the casing which functions as an outlet for the filtered fluid.
Other commercially available filter systems, such as the one disclosed in U.S. Pat. No. 4,735,716 (Petrucci et al.), include a permanently installed fluid head to which a plurality of fluid treatment modules or cartridges are attached. These modules may be attached or detached from the head by merely twisting the module or cartridge to disconnect the module or cartridge from the head. The head is typically made of a plastic type material and includes various threaded inlets and outlets to which the tubing from the external components is connected. The external components may include, for example, the feedwater source, the spigot or faucet, a storage tank and a rejection port.
Further, manufacturing the components of the Petrucci et al. system requires the use of relatively expensive and inefficient manufacturing processes. For example, manufacturing the head of the system requires a number of secondary operations, such as machining and/or drilling to open the fluid channels in the head.
Although the last described system provides a single head to which the individual treatment cartridges may be attached and removed from, it is not without disadvantages.
For example, the tubing from the various external components is typically attached to the inlet and outlet by means of a plurality of brass or plastic fittings. Similarly, connections are provided between the bottom of the cartridges for purposes known in the art are also connected by brass fittings.
Such a fitting/head system has several disadvantages. First, there is a movement to eliminate the use of brass fittings to avoid lead contamination that may be caused by the brass material. Further, since the brass fittings are threaded to a plastic cartridge, the plastic to brass fitting connection is prone to leakage problems. Second, the presently available system described above does not provide any means by which additional accessory components may be easily attached. Third, attaching additional components to available system generally requires that the tubing connected to the various cartridges be cut and adapted such that the additional component may be connected at the cut location.
Further, the filter cartridges are attached to the head by means of a plurality of bayonet type clamps which are used to support the sumps of the filter cartridges. Such clamps are disclosed, for example, in the Petrucci et al. patent. Such clamps include a pair of tab receptacles affixed on the head and a complimentary pair of tabs on each of the cartridges which are engageable with one another by one quarter rotation of the cartridge to lock the cartridge to the head. In the available systems which include a plurality of cartridges, the tab receptacles on the head for adjacent cartridges are formed from a single molded member. That is, the receptacles on the cartridge for affixing two adjacent cartridges are comprised of a single plastic member which includes a tab receptacle for one cartridge on one of its sides and a tab receptacle for an adjacent cartridge on an opposing side. Therefore, the tolerances of the cartridges and the head as well as the tab receptacles must be carefully controlled. In this design the tolerances are critical for accurate alignment of the cartridges since the tolerances are cumulative. That is, the tolerances of one of the cartridges as well as the tolerances of the clamp assembly affect the position of all of the succeeding cartridges. Errors in the tolerances from one cartridge will add to the tolerances from another cartridge in a cumulative manner for the entire length of the head. Therefore, the system is more prone to leaks.
In addition to the above-described problems with the fittings, the available filter systems which use fittings attached to the head at a plurality of different locations on the head make the manifold and cartridge system unsightly. This is particularly important in household applications such as under-the-counter and counter-top units.
Therefore in view of the above, it is a primary object of the present invention to provide a fluid treatment system which obviates the need for brass or other metallic fittings to connect the tubing for external sources and components to the unit and is therefore more reliable against leaks.
It is a further object of the present invention to provide a fluid treatment system which is easier to manufacture than existing systems, particularly a system which is easier to manufacture in different shapes which may be required for packaging of the system.
It is a further object of the present invention to provide a fluid treatment unit wherein the tubing connections to external sources and components may be attached to a manifold which provides intercommunication amongst the cartridges by means of a single non-metallic multiport connector.
It is a further object of the present invention to provide a fluid treatment system wherein accessories such as monitoring and fluid control devices may be easily connected to the fluid treatment system.
It is a further object of the present invention to provide a system wherein the filter cartridges may be easily installed and replaced in the system.
It is still a further object of the present invention to provide a more aesthetic fluid treatment system wherein control and monitoring devices appear as integrated components to the system.